Method and apparatus for the formation of fiber fluff

ABSTRACT

Wood pulp fiber batts of uniform and controlled density are produced by picking fibers from compacted wood pulp and impelling the fibers to a receiving surface passing beneath a multiplicity of panel-like dividers disposed to provide a forming chamber for a unitary batt and to substantially prevent turbulent air currents from the formation zone.

iUmiiied wires ii aiemi Banks aps, 4, 1973 METMoD AND APPARATUS r012 THE2,993,239 7/1961 Heritage l9/l56.3 IFQRMATHQN FKMER FLUFK: 3,016,5821/l962 loa 19/156 3,423,796 1/1969 Nordstrand l9/156.3 [75] Inventor:Charies T. Ranks, Neenah, Wis.

[73] Assignee: Kimheriy-(Ilarlr Corporation,

Ncenah Primary Exammer-Dorsey Newton AttorneyDaniel J. Hanlon, In,William D. Herrick Filed: p 9 W71 and Raymond J. Miller Appl. No.:136,745

Reiafieril US. Application Data Continuation-impart of Ser. No. 647,757,June 21, 1967, abandoned.

11.901. 119/1563 rm. c1 pin 25/00 Field of Search 19/88, 89, 155,156-l56.4, 1 19/205; 156/622 References Cited UNITED STATES PATENTS2,726,423 12/1955 Harwood et al. l9/156.3

[57] ABSTRACT Wood pulp fiber baits of uniform and controlled densityare produced by picking fibers from compacted wood pulp and impellingthe fibers to a receiving surface passing beneath a multiplicity ofpanel-like dividers disposed to provide a forming chamber for a unitarybatt and to substantially prevent turbulent air currents from theformation zone.

7 Claims, 12 Drawing Figures Patented Sept. 4, 1973 5 Sheets-Sheet lFIG.3

Patented Sept. 4, 1973 3,755,856

5 Sheets-Sheet 2 FBG.5

Paten ted Sept. 4, 1973 3,755,856

5 Sheets-Shem 5 mm: mm

mzzm mm cm: mm

Patented Sept. 4, 1973 5 Sheets-Sheet 4 FIG Patented Sept. 4, 1973 5Sheets-Sheet 5 FIG.H

ll lllfi'lllllltlblh AND ATIPATRATIUS FDR TlllE lFOlRlMATllON Gil l lhllh FLUFF This application is a continuation-impart of my pendingapplication Ser. No. 647,757 filed June 21, 1967, now abandoned, andassigned to the same as signee as the present application.

BACKGROUND OF THE lNVENTlON 1. Field of the invention This inventionrelates to wood pulp fiber batts and to apparatus and methods for makingsubstantially continuous lengths of such batts.

2. The invention With Relation To The Prior Art It is common practice toship wood pulp in the form of compacted fibers. The fibers are pressedtogether while wet. Upon drying, the pressed fibers provide a hard,board-like material which withstands shipping conditions well andprovides for reasonable economy in transportation. The fibers may bepicked from such boards and dispersed for the making of fiber slurriesor air formed sheets. I have found that, in the manufacture of airformed sheets, the disintegrator mechanism which picks the fibers shouldbe disposed very closely to the fiber receiving member in order toprovide adequate velocity to the fibers over the distance between thefiberizing area and a receiving surface and overcome electrostaticcharge efi'ects and consequent fiber clumping as the fibers move to thesurface. While such principle is employed in the practice of the presentin vention, l have further found that some non-uniformity in the fiberbatts may result from air currents including windage caused by thepicker mechanism itself. l have now further provided an apparatus andmethod which still further minimizes the tendency toward nonuniformitiesin fluffy fibrous batt formation.

laccomplish the objectives of an improved fibrous batt of uniform andcontrolled density by positioning a forming chamber closely beneath thepicker drum for the fibers and directing the picked or separated fibersthrough the chamber to a receiving surface. The forming chamber isconstructed of a plurality of panels or blades extending in parallelrelation longitudinally in the direction of batt formation and providedin a closely spaced array transversely of the equipment. The panels aresupported below the equipment fiberizing bar and above the fiberreceiving surface on which the batt is formed although in closeproximity to the surface. The receiving surface, whether it be atemporary receiving surface in the nature of a backing for the fibers oras a perforate drum or screen, is subjected to a vacuum pressure toinfluence the retention of the fibers on the receiving surface. Thefiberizing equipment and forming chamber are limitedly open to theatmosphere below the fiberizing bar and zone of picker drum operation.

The batts produced in accordance with the invention achieve gooduniformity because the. fiber velocity in the spacing between thefiberizing bar and receiving surface itself inhibits lateral fibermovement and also because the forming chamber further tends to eliminatelateral fiber movement and fiber clumping.

The invention will be more fully understood by reference to thefollowing detailed description and accompanying drawings wherein:

W6. 1 is a view in perspective of equipment useful in the practice ofthe invention;

FlG. BA is a somewhat enlarged diagrammatic view in perspective withparts removed and others broken away of the arrangement of H6. 1;

FIG. 2 is a side and schematic view of the structure of PEG. 1 withparts removed to particularly illustrate the mode of operation;

FlG. 3 is a view similar to that of FlG. 2 but with a modifiedstructural arrangement;

l lG. is a view in perspective like that of FIG. 1 but illustrating afurther modification of the invention;

H6. 5 is a view in perspective of an element of the forming chamber;

W6. 6 illustrates in plan view and diagrammatically one layoutarrangement of forming chambers in accor dance with the invention forthe production of multiply products;

FIG. 7 is a view in perspective illustrating in greater detail astructural arrangement of components of a forming chamber;

FlG. 8 is a view in perspective like that of FIGS. 1 and 6 illustratinga further modification of the arrangement of the invention;

FIG. 9 illustrates schematically an arrangement of the fiberizingdevices for providing products in multiply form and including indicated.associated vacuum hoods;

FIG. id is a much enlarged view in perspective showing an arrangement ofprimary components of a fiberizer and forming chamber; and

FlG. Ill is a detail view showing an angular disposi tion of thematerial to be fiberizedl with relation to the fiberizing device.

Referring to the drawings more particularly, the numeral 1 in W68. 1 and1A designates a sheet of wood pulp moving in the direction indicated bythe arrow. This sheet may be from a roll source or the supply may be inindividual sheet form. Sheet l is directed (FIG. 1A) through a first set2 of feed rolls comprising an upper and lower series of rolls which gripand move the relatively heavy sheet of wood pulp forwardly. A second setof feed rolls similar to the first is designated at 3 and serves toprovide for minimum load on each roll set while yet providing positivemovement of the sheet The sheet 11 is directed over a fiberizing bardesignated at endwise to a picking roll or drum indicated at 5. Pickingdrum 5' carries a considerable plurality of teeth 6 disposed in spiralrelation about the drum. The picking drum and teeth operate on theprojecting end of the sheet to work on and break up the pulp sheet intosubstantially individual fibers. The fiberizing bar 4 and the pickingdrum 5 extend the full width of a forming chamber which includes passage7 (W68. 2 and 3). Passage 7 is formed between the picking roll 5 and aplurality of forming chamber dividers h in the form of thin panels orblades. The panels are spaced relatively close together and extendacross the width of the machine beneath the picking drum 5 in closeproximity to the drum. The panels or dividers b are themselves supportedfrom the fiberizing bar d as will be discussed more particularlyhereinafterf The picking drum 5 and its associated forming chamber'dividers 8 are spaced immediately above a foraminous receiving surface,one type of which is indicated at 9 in FlG. 2. The teeth of the pickerdrum, that is, the apices of teeth 6, may approach the wire surface asclosely as one-half inch, and such is desirable when the forming chamberpanels b are not utilized. The inclusion of panels permits greaterlatitude in the spacing of the drum and wire while yet achievinguniformity in the product. if the panels are not employed, generally aspacing of not more than about 1% inches should be maintained betweenthe drum or teeth apices and the receiving surface. The foraminoussurface of FIG. 2, as illustrated, is a paper machine forming wirehaving a large number of perforations. Alternatively, the receivingsurface may be an arcuate portion of a foraminous drum 9' in H0. 3. Ineither event, the receiving surface 9 or 9' travels in the directionindicated by the arrow, and a vacuum pressure is exerted on theunderside of the receiving surface to aid receipt on the surface ofdefiberized material directed downwardly in the channel 7 toward thereceiving surface.

Extending the full axial length of the picker drum 5 and around the endsof the drum is a housing 10. This closeness of the housing ill to theteeth 6 is effective to inhibit buildup of fibers in the form of fiberpockets or bundles and which might tend to fall onto a forming sheet andspoil sheet formation. Forwardly, the housing at its lower end, in knownmanner, carries a depending flexible member 25 which is adapted toengage sealing roll 26 and assist in closing off the forward end of theforming chamber to the entry of air. Laterally, the oppositely disposedguides l2 inhibit the flow of air to the forming chamber and define thewidth limits of the forming sheet 13 of pulp fibers.

The forming chamber is open rearwardly below the fiberizer bar 4 andbetween the panels 8 to provide communication of atmospheric pressureair to the un derside of the receiving surface. The forming chamber isotherwise suitably closed to the atmosphere. This communication with theatmosphere provides only a gentle movement of air toward the vacuum zoneand is not a significant factor in fiber movement between the fiberizerbar and the wire 9. This is for the reason that in the practice of theinvention the fibers are impelled at high velocity from the bar in thechannel 7 to the wire and that the energy of the fibers is derivedessentially from the high velocity impact of the picker drum teeth onthe pulp sheet ll. This velocity is of such magnitude that the movementof the fibers laterally is inhibited and receipt of the fibers on thewire is accompanied by a tendency of the traveling fibers to, in effect,bounce, a condition which is minimized by the vacuum condition at thewire surface.

The feeding and fiberizing equipment and the wire 9 may be supported inany convenient manner. As illustrated in H6. 1, angle irons 29 which maybe mounted on framing (not shown) mount plates 30 and an expanded metalsupport 3H engages across the plates and is securely retained thereby.The support 31 is provided with spaced mounting blocks 32 which securethe housings lthlll in position above wire 9. Retaining means 32a aidthis purpose.

The laterally disposed forming chamber dividers or panels 83 haveprojecting ends which extend at least as far forwardly in the directionof receiving surface movement as the center of the picking drum 5 andpreferably somewhat beyond. it is within the zone between the channel 7and panel ends (FIGS. 2 and 3) that the defiberized material movesdownwardly to be received on the surfaces 9 or 9' and form a fine fluffmat or batt l3.

As previously noted, a prior difficulty in the formation of wide widthmats by air deposition of fibers has been the inability to procure matsof substantially uniform thickness over their width. This has been overcome in the present instance: first, by effecting the fiberizing actionvery closely to the receiving surface; and, second, by inhibiting thedevelopment adjacent the fiber receiving surface of air currents whichwould deleteriously influence the fiber deposition. For example, pickingdrum 5, since it rotates very closely to the forming chamber dividers,does not set up the damaging air currents which adversely influencefiber deposition at the receiving surface.

The panels themselves, for the purpose of minimizing air currents in thezone adjacent the receiving surface, have a surface 14 shaped to conformgenerally to the curvature of the drum 5. The surface 14 is very narrowand terminates in a forward vertically extending face 15 and arearwardly disposed upper apex l6. A linear depending wall 17 extendsfrom the apex 116 to the horizontally projecting land l8 which itselfterminates in the rear face 20. The panel faces are, in effect, quitesharp edged designed to avoid or minimize fiber hangup", that is,unwanted fiber retention.

The panel shown at 8 in FlG. 5 has a linear extending base 19 so thatthis latter surface conforms generally with a receiving surface as at 9in W0. 2. More suitably for use with a drum, the surface at 9 isprovided with a slight curvature to conform it to the drum. Exactconformance with the drum or wire is not required but is beneficial tothe attainment of uniform deposition of fiber in mat formation.

Referring now particularly to F165. 1 and 10, the drum 5 may be drivenin the direction indicated by the arrow in any conventional manner, thepicking drum having a shaft 27 for the purpose. Suitably, the drum isformed (FIG. 10) of a plurality of flat plates 5' fixed in side by siderelation on the shaft. Each plate carries in peripherally spacedrelation a plurality of the teeth 6. Teeth 6 may be aligned axially fromplate to plate or may more suitably be in staggered or spiral relationas shown in FIG. 10 so that the incoming pulp sheet 1 is undersubstantially continuous contact by the teeth.

The teeth, I have found, may most suitably be shaped as triangles. Suchconfiguration avoids any significant building of pitch or the likeresulting from contact with the pulp sheet. The included angle of thetooth sides preferably is about 60;a included angle is very effective asto preventing pitch buildup but requires more power for the same actionon the pulp. Teeth with included angles of up to 90 serve the purpose,however, and the nature of the pulp itself will have a bearing on theextent of nit formation, that is, the tendency of fibers to cluster; Itis, of course, not necessary that the teeth be triangular and othershapes serve the purpose well.

The incoming pulp sheet may be subjected to the teeth over a relativelywide range of angular contact with the teeth. Preferably, the angle ofcontact is (FlG. 11) acute so that fibers tend to be both picked andwiped from the sheet. The teeth are intended to travel at relativelyhigh speeds of about 4000 fpm and up and are selected in view of thedensity of the pulp undergoing the fiberizing action, higher tooth ordrum speeds being more suitable at higher pulp sheet densities. At highspeeds, the fibers removed from the sheet are carried by the force ofthe impact in the channel 7 and forming chamber toward the wire 9 asalready discussed. The velocity of the fibers due to the impact of theteeth is the controlling factor in fiber movement to the wire.

The fiberized material passes downwardly to the foraminous surface wellwithin the limits of the length of the panel b (FIGS. 2 and 3). Thedeposited mat has a high degree of uniformity varying only about i 2percent in all directions in weight over a web having a substantiallycontinuous length. This small variation has been found in trial widthsof about 12% and it is anticipated may be maintained substantiallyindependent of the width. Such uniformity is attained by appropriatelyspacing the panels 8. Spacing at a distance of only about one inch apartand one-half inch above the fiber receiving surfaces is effective toprovide communicating compartments of a width which is narrow relativeto the width of the mat undergoing fiberization. Close proximity to thefiber receiving surface by the base of the panel 3 is desirable toprevent unwanted air flow between the chambers defined by the panels.Cross air flow is, in fact, essentially eliminated by the panels in thepreferred practice of the invention.

Referring now to FIG. d, the structural arrangement is similar to thatof FIG. I except that a plurality of sheets are being fed individuallyto individual drums 5 and the fibers are directed to a common receivingsurface. In this instance the panels associated with the forward drum 5aare offset slightly transversely of the equipment from the panelsassociated with the first drum 5. Also, the fiberizing drum ordisintegrators of succeeding units may be spaced a greater distance fromthe fiber receiving member as may the panels to provide for clearance sothat previously deposited fibers are not disturbed by a succeedingdeposit.

As more clearly shown in FIG. 6, wherein the elements representing thepanels are indicated at 8a, more than one set of panels may be offsetfrom theinitial group. For example, three sets may be disposed toprovide, in effect, a great plurality of width-wise overlapping formingchambers, each of small widthwise dimension. The chambers, however, docommunicate with each other, particularly in the transverse direction byvirtue of the raised position (FIGS. 2 and 3) of the panels 8.

In another variation of the arrangement in accor dance with theinvention, the mat fed to the second, for example, of a series ofpicking drums may be more narrow than preceding or succeeding mats.Thus, as indicated at Ia in FIG. h, the mat may be quite narrow and isfed centrally to the device to cause a deposition of a second mat 211 ona first mat I3, the second mat ZI being more narrow and derived from thepulp mat Ia. This provides for a controlled width of material of acontoured nature in the present instance more thick centrally than atthe edges. Also, as illustrated in FIG. 8, the fiber deposition may beon a base sheet 34 of suitable nature to form a part of the finalproduct, that is, tissue paper, film or the like.

A plurality of the fiberizing and forming chamber heads may be arrangedin position to deposit very considerable thicknesses of fluff or toprovide positioned thicknesses as in FIG. 8. As shown in FIG. 9, thevacuum boxes 33 then are preferably disposed so that the spacing 35between boxes lies under the seal roll 26 to thus inhibit air loss. Thearrows in FIG. 9 indicate the direction of air movement.

The positioning of the panels 8 closely adjacent the drums 5 is of majorimportance if the unwanted influence of air flow is to be avoided. Mostsuitably, the panels are supported by being pressed upwardly into slots22 of the fiberizing bar I, as most clearly illustrated in FIG. 7. Thefiberizing bar 4 may be supported, of course, by any convenient means(not shown).

In specific application with the pulp sheet fed at a rate of about 20fpm to the picker drum, the drum was driven at 5400 fpm. Each plate ofthe drum (FIG. 10) carried 6 teeth and the teeth were arranged spirallyabout the drum. The drum diameter was about 6 inches and the sheet wasfed to the drum as illustrated in FIG.

II. The quality of the fluff deposited on the receiving surface wasexcellent, and the formed sheet varied in weight to the extent of onlyabout i- 2 percent. The rate of feed of the pulp is dependent, for aspecific fiber quality, on the nature of the material being fiberized.Very hard pulps havebeen successfully formed into fluffy batts at a feedrate of the pulp of 60 fpm while softer pulps have performed well atfpm.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined in the appended claims.

I claim:

I. In combination, in apparatus for forming a continuous layer of woodpulp fibers, roll picker means and a fiberizing bar for defiberizing tosubstantially individual fibers a mat of the wood pulp fibers, means forfeeding a mat of the wood pulp fibers to the said bar and roll pickermeans, a forming chamber closely adjacent the periphery of and below theroll picker means, and a receiving surface communicating with saidforming chamber, said forming chamber having a plurality of panelsprojecting longitudinally in the direction of the receiving surface inlaterally spaced apart relation defining small compartmentscommunicating the picker roll periphery and receiving surface, saidpanels inhibiting air flow between compartments and being disposedslightly above the receiving surface to provide a continuous laterallyextending zone on the receiving surface for fiber deposition, the saidforming chamber being open to the atmosphere below the fiberizing barand the said receiving surface having communication with a vacuumchamber.

2. Apparatus as claimed in claim I and in which panels defining theforming chamber extend in the direction of the receiving surface beyondthe picker roll center from rearwardly of the picker roll.

3. Apparatus as claimed in claim. I and in which the panels aresupported by and depend from the fiberizing bar and have a contourconforming to that of the picker roll and extend from the fiberizing barbeneath the picker forwardly of the picking roll center.

4. Apparatus for forming a continuous layer of wood pulp fibers from amat of such fibers, said apparatus comprising a movable fiber receivingsurface, a housing disposed above said fiber receiving surface forpassage of the fiber receiving surface relative to the housing, rollpicker means within the housing, a fiberizing bar, means for feeding asaid mat of the fibers to said fiberizing bar and roll picker means sothat said mat may be defiberized substantially individual fibers, aforming chamber between the receiving surface and roll picker means andhaving a plurality of panels extending longitudinally with and above thereceiving surface defining narrow compartments, said forming chamberhaving an opening to the atmosphere rearwardly of the compartments andbelow the fiberizing bar, and vacuum chamber means in communication withsaid opening through said receiving surface and said forming chamber.

5. Apparatus as claimed in claim 4 and in which a plurality offiberizing bars and associated roll picker means are disposed in linearrelation above a common receiving surface, and a forming chamberassociated with each fiberizing bar-roll picker means combination, thepanels of successive forming chambers being offset from each otherlaterally.

6. The method of forming a batt of pulp fibers which comprises formingin air a plurality of streams of substantially individual fibers withsaid streams in longitudinally spaced apart relation, directing thefiber streams toward a longitudinally moving common surface so that thefibers of the streams are superposed in layers on the said surface,limiting lateral movement of the fibers of each stream as it approachesthe common surface by guiding each stream through a plurality ofparallel disposed compartments and so that each stream is subdividedlaterally, at least one compartment of one said plurality ofcompartments being disposed in slightly offset relation laterally tocompartments of a subsequent plurality of parallel disposed compartmentsso that fibers of successive streams overlap laterally. 1

7. The method of forming a batt of pulp fibers which comprises formingin air a plurality of streams of substantially individual fibers withsaid streams in longitudinally spaced apart relation, directing thefiber streams toward a longitudinally moving common surface so that thefibers of the streams are superposed in layers on the said surface,limiting lateral movement of the fibers of each stream as it approachesthe common surface by guiding each stream through a plurality ofparallel disposed compartments and so that each stream is subdividedlaterally, and forming initially one of said streams of said pluralityof streams of a width which is significantly less than the width of atleast one other of said streams so that a contoured batt is formed.

1. In combination, in apparatus for forming a continuous layer of woodpulp fibers, roll picker means and a fiberizing bar for defiberizing tosubstantially individual fibers a mat of the wood pulp fibers, means forfeeding a mat of the wood pulp fibers to the said bar and roll pickermeans, a forming chamber closely adjacent the periphery of and below theroll picker means, and a receiving surface communicating With saidforming chamber, said forming chamber having a plurality of panelsprojecting longitudinally in the direction of the receiving surface inlaterally spaced apart relation defining small compartmentscommunicating the picker roll periphery and receiving surface, saidpanels inhibiting air flow between compartments and being disposedslightly above the receiving surface to provide a continuous laterallyextending zone on the receiving surface for fiber deposition, the saidforming chamber being open to the atmosphere below the fiberizing barand the said receiving surface having communication with a vacuumchamber.
 2. Apparatus as claimed in claim 1 and in which panels definingthe forming chamber extend in the direction of the receiving surfacebeyond the picker roll center from rearwardly of the picker roll. 3.Apparatus as claimed in claim 1 and in which the panels are supported byand depend from the fiberizing bar and have a contour conforming to thatof the picker roll and extend from the fiberizing bar beneath the pickerforwardly of the picking roll center.
 4. Apparatus for forming acontinuous layer of wood pulp fibers from a mat of such fibers, saidapparatus comprising a movable fiber receiving surface, a housingdisposed above said fiber receiving surface for passage of the fiberreceiving surface relative to the housing, roll picker means within thehousing, a fiberizing bar, means for feeding a said mat of the fibers tosaid fiberizing bar and roll picker means so that said mat may bedefiberized substantially individual fibers, a forming chamber betweenthe receiving surface and roll picker means and having a plurality ofpanels extending longitudinally with and above the receiving surfacedefining narrow compartments, said forming chamber having an opening tothe atmosphere rearwardly of the compartments and below the fiberizingbar, and vacuum chamber means in communication with said opening throughsaid receiving surface and said forming chamber.
 5. Apparatus as claimedin claim 4 and in which a plurality of fiberizing bars and associatedroll picker means are disposed in linear relation above a commonreceiving surface, and a forming chamber associated with each fiberizingbar-roll picker means combination, the panels of successive formingchambers being offset from each other laterally.
 6. The method offorming a batt of pulp fibers which comprises forming in air a pluralityof streams of substantially individual fibers with said streams inlongitudinally spaced apart relation, directing the fiber streams towarda longitudinally moving common surface so that the fibers of the streamsare superposed in layers on the said surface, limiting lateral movementof the fibers of each stream as it approaches the common surface byguiding each stream through a plurality of parallel disposedcompartments and so that each stream is subdivided laterally, at leastone compartment of one said plurality of compartments being disposed inslightly offset relation laterally to compartments of a subsequentplurality of parallel disposed compartments so that fibers of successivestreams overlap laterally.
 7. The method of forming a batt of pulpfibers which comprises forming in air a plurality of streams ofsubstantially individual fibers with said streams in longitudinallyspaced apart relation, directing the fiber streams toward alongitudinally moving common surface so that the fibers of the streamsare superposed in layers on the said surface, limiting lateral movementof the fibers of each stream as it approaches the common surface byguiding each stream through a plurality of parallel disposedcompartments and so that each stream is subdivided laterally, andforming initially one of said streams of said plurality of streams of awidth which is significantly less than the width of at least one otherof said streams so that a contoured batt is formed.